The present invention relates to a drive arrangement, in particular for a mill, and to a method for operating a drive arrangement.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
DE 202009016825 U1 describes a roller mill, which includes a housing, a grinding table with a grinding track and grinding rollers rolling on the grinding track, wherein during operation the grinding rollers can be disengaged. The roller mill also includes at least two drives with a motor and gearing, which drive the grinding table. In order to be able to equalize the design-related or also deliberately chosen differences in the properties of the drives, i.e. in the properties of the electric motors and the reduction gearing, a turbo coupling is assigned to at least one of the gearings, preferably to each gearing. The torque characteristic curve of the turbo couplings is selected such that the different properties of the drives are compensated so that each drive drives the grinding table with its nominal power.
A turbo coupling, also known under the term “fluid coupling” is a hydrodynamic coupling, in which in the entire operating range the power is transmitted hydrodynamically according to the Fottinger principle.
Fluid couplings heat up during operation, particularly during starting operations. It is possible here that a temperature reserve toward a maximum permissible temperature of the fluid coupling is too low for a possibly repeated starting operation of a drive, because the fluid coupling from a previous operation of the drive is heated again. The heat discharge from the fluid couplings to the ambient air generally takes place by means of convection. When the drive is stationary, there is only free convection and the fluid coupling requires a very long time, in some instances several hours, to cool down before a start of the drive, in particular a startup under high load, is possible again. Wait times resulting therefore indicate a loss in production and are unwanted.
It would therefore be desirable and advantageous to address these problems and to obviate other prior art shortcomings.